It’s not every day paleontologists find a dinosaur with lunch still wedged in its teeth. But in Patagonia, researchers just pulled that off.
In a fossil bed dating back 68 million years, scientists discovered the remains of a new species of megaraptor — a lithe, clawed predator that ruled South America’s ecosystems just before the asteroid struck. And in the jaws of this predator, named Joaquinraptor casali, they found the leg bone of an ancient crocodile relative.
“This is a fantastic discovery and one of the most intriguing new dinosaur discoveries in recent memory,” said Steve Brusatte, a paleontologist at the University of Edinburgh who was not involved in the study, in an interview with Live Science.
A Raptor Without T. rex Problems
Joaquinraptor stretched about 7 meters (23 feet) from nose to tail and weighed over a metric ton. Unlike the bulky T. rex of North America, this dinosaur was slender, fast, and armed with enormous claws.
“Joaquinraptor was slender and svelte and fast, and it had ridiculously oversized arms and claws, like hedge trimmers,” Brusatte explained. “Its arms and hands make T. rex look puny by comparison, Arnold Schwarzenegger vs Danny DeVito, at least in the arms category.”
Those claws — hypertrophied weapons on the first two digits — may have been used to slash at prey or tear into soft tissue. As Lucio Ibiricu of the Patagonian Institute of Geology and Paleontology, the study’s lead author, told ScienceAlert, “Megaraptorids, among other aspects, are characterized by powerfully developed forelimbs equipped with hypertrophied claws … to access soft tissues and/or to aid in prey capture and manipulation.”
The discovery fills in missing details about the evolution of megaraptors, a clade of theropods that dominated southern continents while tyrannosaurs stomped the north. Unlike their northern counterparts, these raptors remained sleek and ferociously agile.
Crocodile on the Menu
The fossil record rarely hands paleontologists a clear picture of diet. But Joaquinraptor left a jarring clue: a crocodyliform humerus lodged between its jawbones.
“Interestingly, we recovered a humerus, between the lower jaw bones of Joaquinraptor, suggesting — though not proving — that the new megaraptor may have been eating the crocodyliform when it died,” Ibiricu told ScienceAlert.
To rule out coincidence, the researchers examined the bone. It bore tooth marks and rested against the dinosaur’s teeth — a strong hint of interaction, whether the raptor had been in mid-meal or mid-fight. As the authors of the new study wrote in Nature Communications, “the preservation of a crocodyliform humerus between the dentaries of the new theropod may provide information on megaraptoran dietary preferences and feeding strategies.”
In other words, if you were a crocodile ancestor in late Cretaceous Patagonia, this raptor might have been your worst nightmare.
The Last of Its Kind
Joaquinraptor lived right at the twilight of the Cretaceous, only a few million years before the Chicxulub asteroid ended non-avian dinosaurs.
“Deemed the latest surviving megaraptoran, this fossil provides insight into the final phase of their evolutionary history in South America prior to the mass extinction,” Darla Zelenitsky, a paleontologist at the University of Calgary, who was not involved in the study, told Live Science.
Bone histology revealed that the individual was at least 19 years old, sexually mature but not yet fully grown. That means Joaquinraptor may have reached even larger sizes had it lived longer.
Its world was not the dry scrub of modern Patagonia. Fossilized sediment paints a picture of a humid floodplain near the sea, buzzing with life. Joaquinraptor would have prowled this ecosystem as its apex predator, filling the role tyrannosaurs played up north.
Joaquinraptor’s discovery doesn’t just add a new villain to the dinosaur pantheon — though Hollywood should definitely take notes. It provides major insights into the last days of southern predators. These raptors weren’t fading away. They were thriving, razor-clawed and fast, until a giant rock from space changed everything.
